Kings of Denmark in the context of Holstein-Glückstadt

The Dannebrog (Danish: Dannebrog, pronounced [ˈtænəˌpʁoˀ]) is the flag of Denmark. The flag is red with a white Nordic cross, which means that the cross extends to the edges of the flag and that the vertical part of the cross is shifted to the hoist side.

A banner with a white-on-red cross is attested as having been used by the kings of Denmark since the 14th century. An origin legend with considerable impact on Danish national historiography connects the introduction of the flag to the Battle of Lindanise of 1219.

The Duchy of Estonia (Estonian: Eestimaa hertsogkond, Danish: Hertugdømmet Estland Latin: Ducatus Estoniae), also known as Danish Estonia, was a direct dominion (Latin: dominium directum) of the King of Denmark from 1219 until 1346 when it was sold to the Teutonic Order and became part of the Ordensstaat.

Denmark rose as a great military and mercantile power in the 12th century. It had an interest in ending the frequent Estonian attacks that threatened its Baltic trade. Danish fleets attacked Estonia in 1170, 1194, and 1197. In 1206, King Valdemar II and archbishop Andreas Sunonis led a raid on Ösel island (Saaremaa). The Kings of Denmark claimed Estonia, and this was recognised by Pope Honorius III. In 1219, the fleet of Valdemar II landed in the harbor of Lindanise (Tallinn) and defeated the local Estonians in the Battle of Lindanise. This brought northern Estonia under Danish rule until the Estonian uprising in 1343, after which the territories were taken over by the Teutonic Order. They were sold by Denmark in 1346.

The Duchy of Holstein (German: Herzogtum Holstein; Danish: Hertugdømmet Holsten) was the northernmost state of the Holy Roman Empire, located in the present German state of Schleswig-Holstein. It originated when King Christian I of Denmark had his County of Holstein-Rendsburg elevated to a duchy by Emperor Frederick III in 1474. Members of the Danish House of Oldenburg ruled Holstein – jointly with the Duchy of Schleswig – for its entire existence.

From 1490 to 1523 and again from 1544 to 1773 the Duchy was partitioned between various Oldenburg branches, most notably the dukes of Holstein-Glückstadt (identical with the Kings of Denmark) and Holstein-Gottorp. The duchy ceased to exist when the Kingdom of Prussia annexed it in 1866 after the Austro-Prussian War.

Southern Jutland (Danish: Sønderjylland; German: Südjütland) is the region south of the Kongeå in Jutland, Denmark and north of the Eider (river) in Schleswig-Holstein, Germany. The region north of the Kongeå is called Nørrejylland, 'Northern Jutland'. Both territories had their own ting assemblies in the Middle Ages (in Viborg and Urnehoved). Southern Jutland is mentioned for the first time in the Knýtlinga saga.

In the 13th century South Jutland became a duchy. The first duke was Canute Lavard (Knud Lavard). In the late 14th century, House Schauenburg orchestrated a political coup led by the German prince Gerhard III. One of his most symbolic actions was renaming the duchy. 'South Jutland' was a distinctly Danish term, linking the region to North Jutland and reinforcing its connection to Danish identity and the Kingdom of Denmark. Gerhard aimed to sever these ties and anchor the duchy more firmly within the German cultural sphere. As a result, the region was renamed the Duchy of Schleswig. The new name derived from the city of Schleswig (Slesvig). Naming duchies after their principal cities was a common German ducal practice, as seen in examples such as the Duchies of Brunswick (Braunschweig), Mecklenburg, Magdeburg, Anhalt, and others. The dukes of Schleswig also became kings of Denmark.

The Duchy of Estonia (Estonian: Eestimaa hertsogkond, Danish: Hertugdømmet Estland, Latin: Ducatus Estoniae), also known as Danish Estonia, was a direct dominion (Latin: dominium directum) of the King of Denmark from 1219 until 1346 when it was sold to the Teutonic Order and became part of the Ordensstaat.

Denmark rose as a great military and mercantile power in the 12th century. It had an interest in ending the frequent Estonian attacks that threatened its Baltic trade. Danish fleets attacked Estonia in 1170, 1194, and 1197. In 1206, King Valdemar II and archbishop Andreas Sunonis led a raid on Ösel island (Saaremaa). The Kings of Denmark claimed Estonia, and this was recognised by Pope Honorius III. In 1219, the fleet of Valdemar II landed in the harbor of Lindanise (Tallinn) and defeated the local Estonians in the Battle of Lindanise. This brought northern Estonia under Danish rule until the Estonian uprising in 1343, after which the territories were taken over by the Teutonic Order. They were sold by Denmark in 1346.